The term “inerting spaces” refers to the process of displacing, from spaces, atmospheric oxygen or potentially reactive or explosive gases or gas mixtures, by means of the addition of non-reactive (inert) gases or vapours to oxygen in air. In the process of inerting a gas volume for the purpose of protection against fire and/or explosion, atmospheric oxygen is displaced by the addition of inert gas, for example rare gas such as argon, but also nitrogen or carbon dioxide, so as to prevent the forming of a potentially explosive atmosphere. In the context of fire protection this is also referred to as active fire prevention by permanent inerting.
For approximately 40 years, halons have been used for extinguishing fires on board aircraft. Halons are partially- or entirely halogenated hydrocarbons that chemically intervene in the chain reaction of a fire, thus resulting in termination of the reactions.
However, in Germany halon fire extinguishers are no longer permitted, because halons have a detrimental effect on the ozone layer. With the halons 1211 and 1301 (bromochlorodifluoromethane and bromotrifluoromethane) having disappeared from the market as a result of the Montreal Protocol, some companies in the meantime are marketing new halons for firefighting purposes, which new halons are said to be unproblematic from the point of view of any ozone-depleting effect. At least some of these halons have already obtained EU approval. WO 2007/054316 A1 and WO 2007/054314 A1 disclose a firefighting system for extinguishing a fire in a space in an aircraft by means of a fuel cell.